In a small, affluent community outside Denver, an under-construction limestone castle with 126 custom-made chandeliers and a “breakfast turret” is going on the market for $17.5 million.

If it sells for anywhere near its asking price, “Chateau V” will be the most expensive home ever to sell in the community of Evergreen, said Whitney Cain of LIV Sotheby’s International Realty, one of the listing agents. She said the highest priced sale in recent memory was about $9 million; the median sales price in Evergreen is $535,000, according to Trulia.

Chateau V is owned by Randall and Cynthia Veselka, Texas natives who run the financial-services company DTI Credit. They said they started building the house about eight years ago, inspired by the Biltmore Estate in North Carolina and by castles they saw on trips to Europe.

The couple said they’ve decided to sell because they spend much of their time traveling and visiting their grandchildren. They said work continues on the château, but they wanted to put it on the market now so that potential buyers can complete it to their own specifications.

The roughly 20,000-square-foot château sits on about 35 acres with mountain views from nearly every room, Ms. Cain said. When completed, it will have five bedrooms and eight fireplaces. Each of the 12 dormer windows are flanked by statues Ms. Veselka modelled after similar ones she saw in Monaco. The roof, topped with a fleur-de-lis iron railing, has a deck that Mr. Veselka said he’d envisioned using to hit golf balls into the valley below.

For the windows of two spiral staircases, Ms. Veselka designed a series of family crests with the names of their five children and other family members. A light-up Chateau V crest is emblazoned on each end of a kitchen island.

All of the bedrooms have en-suite bathrooms, each with a washer and dryer. A children’s play room off the library is concealed behind a hidden door, and a dog shower is adjacent to an outdoor dog run.

In the roughly 5,000-square-foot basement, the couple had planned to build an indoor/outdoor swimming pool, a home theater and an entertainment area, but those elements haven’t been built yet.